Perhaps less then a full revolution.

I imagine this could mean many things.

It's a 157 watt Astec AA13740 / IBM 62x1139. Allegedly for an XT/286.

Apparently it starts and wants to keep running, but is made to immediately shut down. I haven't opened it, nor metered it.

I always wind up with these weirdos. I bought an unbranded vanilla clone at a sale for 20$. Inside was a DTK Mobo and a BLACK IBM PC p/s.